3-4 TANK ASSEMBLY REPAIR (CONT) .
Weld small gouges, cracks, or punctures in tank or cracks at fitting or tank welds as follows:
Although not as flammable as gasoline, diesel fuel is volatile and the vapor will burn
or explode. To avoid injury to personnel do not weld fuel tank, or perform other
operations that may produce sparks, until fuel tank is rendered safe. Live steam used
for cleaning shall not exceed 100 psi (690 kPa). During steam cleaning operations,
adequate ventilation, natural or forced, should be provided. Do not direct live steam
Do not weld patches on tank. If damage is not repairable without patch, replace the tank.
a. Steam clean inside of fuel tank for at least four hours. During this time, high pressure steam should be introduced
alternately into all openings to vaporize and flush away all residual fuel.
b. At end of steaming period, check for residual fuel vapors using explosive vapor detector. If explosive vapors are
detected, repeat steam cleaning.
Welding operations produce heat, highly toxic fumes, injurious radiation, metal slag,
and airborne particles. Welding mask with properly tinted lens, apron or jacket, and
welders boots are required to avoid injury to personnel.
c. Weld as required in accordance with TM 9-237.
Test tank assembly after welding as follows:
Plug all openings except filler cap opening.
Apply and maintain an air pressure of 3 psi (21 kPa) to tank assembly through filler cap opening.
Apply soap solution to all repaired areas and suspected leak areas and check for bubbles. Bleed off air and
Use emery cloth to smooth out repaired areas and repaint.
Replace tank assembly in accordance with paragraph 2-22.